title: Genetic heterogeneity and clinical variability in the Sanfilippo syndrome (types A, B, and C).
abstract: A study of 73 patients with the Sanfilippo syndrome (36 patients with Sanfilippo A disease, 23 with Sanfilippo B disease and 14 with Sanfilippo C disease) revealed both intertype and intratype variability. The course of the disease was relatively mild in Sanfilippo B disease and dementia was less severe. Type A showed earlier onset with more severe clinical manifestations and an earlier age at death. Sanfilippo C disease was slightly less severe than Sanfilippo A disease. The intratype variability may be explained in part by differences in genetic and environmental background. In Sanfilippo B disease, genetic heterogeneity is suggested by the observation of a more severe and a mild variant, and this variation may be due to the involvement of different allelic mutations. The intrafamilial variability of the different types was small, but in three families with Sanfilippo B disease intrafamilial variability was evident.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003704:Dementia / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D008297:Male; D009083:Mucopolysaccharidoses / Q000235:genetics*; D009084:Mucopolysaccharidosis III / Q000145:classification / Q000235:genetics* / Q000401:mortality